Semiconductor device

ABSTRACT

A trench is formed in an insulation film formed on top of a semiconductor substrate, and a barrier metal film is formed on the surface of the trench. After a copper or copper alloy film is formed on the barrier metal film, an oxygen absorption film in which a standard energy of formation of an oxidation reaction in a range from room temperature to 400° C. is negative, and in which an absolute value of the standard energy of formation is larger than that of the barrier metal film is formed, and the assembly is heated in a temperature range of 200 to 400° C. A semiconductor device can thereby be provided that has highly reliable wiring, in which the adhesion to the barrier metal film in the copper interface is enhanced, copper diffusion in the interface is suppressed, and electromigration and stress migration are prevented.

TECHNICAL FIELD

The present invention relates to a semiconductor device having wiring,and particularly relates to a semiconductor device composed of a trenchwiring (damascene wiring) structure having copper as the primarycomponent, and to a method for manufacturing the semiconductor device.

BACKGROUND ART

Aluminum (Al) or Al alloy has been widely used in the past as theconductive material in silicon semiconductor integrated circuits (LSI).Copper (Cu) has come to be used as the conductive material in order toincrease reliability and reduce wiring resistance in the wiring inconjunction with advances in LSI miniaturization.

Since processing by dry etching is difficult, a damascene method isgenerally used when the copper wiring is formed. The damascene method isa method whereby copper is filled into a wiring trench and/or a viaformed in an insulation film on the semiconductor substrate, and wiringis formed by polishing off and removing the excess copper.

The dimensions of wiring have become smaller in recent years inconjunction with LSI miniaturization, and disconnection defects incopper wiring are a serious problem. Copper migration is a contributingfactor to wiring disconnection defects. Copper migration can be broadlyclassified into two types according to drive power. One type iselectromigration, which is caused by current flowing in the wiring, andthe other type is stress migration, which is caused by stress in thewiring. The current density flowing in the wiring increases as thewiring becomes smaller, and migration of copper easily occurs due toelectric wind. A stress gradient occurs at the minute junction of a viaand the wiring, and migration of copper occurs in order to alleviate thestress.

Copper migration easily occurs at copper grain boundaries and theinterface of different types of material between the copper and thesurrounding film. The reason for this is that the activation energy ofcopper diffusion at these locations is smaller than that of the coppervolume diffusion. In order to prevent diffusion of copper, the stabilityof the copper grain boundaries must be increased, and the adhesionbetween the copper and the surrounding film must be enhanced.

A method for adding an additive element to the copper wiring to create acopper alloy has been reported as a method for preventing coppermigration. In Patent Document 1, an alloy in which silver or the like isadded to copper is used as a copper alloy. Methods for forming a copperalloy film in which these elements are added include a sputtering methodthat uses a target as an alloy to which the additive is added, a methodfor forming alloys from platings of tin or chromium with copper, and amethod for forming an alloy by a CVD method or the like.

There is also a method whereby a film having a function for enhancingadhesion with copper is provided to a barrier metal part. In PatentDocument 2, a technique is disclosed for forming a film composed of amaterial having good adhesion with copper on a barrier metal that isformed by chemical vapor deposition or ALD, whereby electromigrationdefects and the like are prevented, and the reliability of the wiring isenhanced.

Patent Document 1: Japanese Laid-open Patent Application No. 9-289214

Patent Document 2: Japanese Laid-open Patent Application No. 2003-332426

DISCLOSURE OF THE INVENTION Problems the Invention is Intended to Solve

Conventional techniques include methods for alloying the wiring itself,as described in Patent Document 1, and methods for enhancing theadhesion between the copper and the surrounding barrier metal film, asdescribed in Patent Document 2. However, the conventional techniqueshave such problems as the ones described below.

(1) When another metal element is added to copper wiring to createcopper alloy wiring, the copper grain boundaries can be stabilized,diffusion of copper in the boundary portions can be suppressed, and thereliability of the wiring can be enhanced. However, when diffusion ofcopper more easily occurs at the interface of the copper with adifferent type of material, diffusion of copper occurs with priority atthe boundary portions. Therefore, a technique is needed for increasingadhesion of the copper with the surrounding material and preventingcopper migration. Particularly since copper or copper alloy adherespoorly to an oxide, interface oxidation in the interface region must besuppressed.

(2) When a barrier metal film having a high degree of adhesion to copperis used, copper diffusion at the interface is suppressed, andreliability can be increased. However, when the wiring is formed by adamascene method, problems occur in that oxygen diffused in the copperfilm oxidizes the barrier metal film during the heating step from thenatural oxide film on the surface of the copper that is filled into thewiring trenches. The diffusion rate of oxygen is high particularly atthe copper grain boundaries, and severe oxidation of the barrier metalfilm is observed in the portions where the barrier metal surface is incontact with the copper grain boundaries. The natural oxidation rate ofthe copper film surface is high, and even when the surface oxide film istemporarily removed prior to the heating step, it is difficult toprevent oxidation of the barrier metal film, which is generally composedof a material that oxidizes more easily than copper. Since the adhesionbetween the copper film and the oxidized barrier metal filmdeteriorates, a technique is needed for preventing oxidation of thebarrier metal film due to oxygen diffusion from the natural oxide filmof the copper surface during the heating step. Oxygen included as animpurity in the copper film is also moved by the heating step to theinterface, which is a more stable potential field, and a technique istherefore needed for reducing the oxygen concentration in the copperfilm. Oxygen in a copper film or copper alloy film takes electrons fromcopper atoms (Cu) in the metal state to form oxygen ions (O²⁻), and thecopper atoms in the metal state are also changed to ions (Cu⁺, Cu²⁺).These ions are moved by an electric field, and therefore cause reducedwiring reliability.

An object of the present invention is to provide a semiconductor devicehaving highly reliable wiring in which adhesion with the barrier metalfilm in the copper interface is enhanced, copper diffusion in theinterface is suppressed, and electromigration and stress migration areprevented, and to provide a method for manufacturing the semiconductordevice.

Means for Solving the Problems

The semiconductor device manufacturing method of the present inventionis characterized in comprising (a) a step for forming a trench and/or avia for forming wiring, in a prescribed region in an insulation filmformed on top of a semiconductor substrate, (b) a step for forming abarrier metal film on the insulation film in which the trench and/or viais formed, (c) a step for forming a copper or copper alloy film on thebarrier metal film, (d) a step for forming on the copper or copper alloyfilm an oxygen absorption film in which a standard energy of formationof an oxidation reaction in a range from room temperature to 400° C. isnegative, and in which an absolute value of the standard energy offormation is larger than that of the barrier metal film formed in the(b) step, (e) a step for heating a layered film composed of the barriermetal film, the copper or copper alloy film, and the oxygen absorptionfilm in a temperature range of 200 to 400° C., and (f) a step forremoving an upper part of the layered film and forming wiring.

The copper or copper alloy film formed in the (c) step may be a copperplating film having a copper alloy film as a seed in which a solidsolution is formed with an added element for which the absolute value ofthe standard energy of formation of the oxidation reaction in the rangefrom room temperature to 400° C. is larger than that of the barriermetal film.

A configuration may be adopted in which the copper or copper alloy filmformed in the (c) step is a copper plating film having the copper alloyfilm as a seed in which a solid solution is formed with an addedelement; and the absolute value of the standard energy of formation ofthe oxidation reaction of the added element is larger than that of thebarrier metal film, and is equal to or less than that of the metal thatconstitutes the oxygen absorption film formed in the (d) step.

A thickness of the oxygen absorption film formed in the (d) step may be100 Å or less.

A configuration may also be adopted in which the barrier metal film istantalum, tantalum nitride, or a layered film thereof, and the oxygenabsorption film is formed by a film having aluminum, titanium,magnesium, calcium, zirconium, beryllium, hafnium, or silicon as aprimary component.

The semiconductor device according to the present invention is asemiconductor device having a copper or copper alloy film positioned inat least one layer, and a barrier metal film for covering a periphery ofwiring that is formed in a prescribed region in an insulation filmformed on top of a semiconductor substrate; wherein the semiconductordevice is characterized in that an oxide of the barrier metal film isnot present in a region in which the copper or copper alloy film is incontact with the barrier metal film.

Furthermore, a concentration of oxygen included in the copper or copperalloy film is preferably 4×10¹⁸ atoms/cm³ or less in a wiring internalportion other than an interface region with the barrier metal film. Inthe case of a copper plating film in which a copper alloy seed film isformed as a seed in which an added element forms a solid solution in thecopper alloy film, an oxide of the barrier metal film is not present,and an oxygen concentration peak is present in the plating filminterface with the copper alloy seed film in the region in which thebarrier metal film is in contact with the copper or copper alloy film.At this time, the concentration of the added element is high in a copperalloy seed film region of the copper or copper alloy film, and theconcentration of the added element is low in a copper plating filmregion.

In the present invention, the term “oxide of the barrier metal” refersto an oxide of the barrier metal that is formed in the interface regionof the barrier metal and the copper or copper alloy film. Since thevolume of the barrier metal is increased through oxidation, the barriermetal is formed to have a certain thickness with the interface region ofthe barrier metal and the copper or copper alloy at the center. Thepresence of an oxide of the barrier metal can be determined by elementalanalysis by SIMS (Second Ion Mass Spectroscopy), or TEM (TransmissionElectron Microscopy) analysis. In the case of SIMS analysis, the oxygenconcentration is analyzed with the interface region of the barrier metaland the copper or copper alloy at the center. When an oxide of thebarrier metal is not present, there is no peak or inflection point inthe oxygen concentration profile, and the profile decreases or increasesmonotonically in the interface of the barrier metal with the copper orcopper alloy. When an oxide of the barrier metal is present, a peak oran inflection point is present in the oxygen concentration profile inthe interface of the barrier metal and the copper or copper alloy, andthe profile no longer increases monotonically or decreasesmonotonically. In a depth-direction analysis by SIMS, since measurementis performed during sputtering, the portion detected as the interfacedoes not have a steep concentration gradient, as in the actualstructure, and the interface region and the presence of barrier metaloxidation can therefore be determined by the change in the profile, asdescribed above. A state in which “an oxide of the barrier metal is notpresent” in the present invention is a state in which a peak or aninflection point is not present in the oxygen concentration profile, andthe profile decreases or increases monotonically in the interface of thebarrier metal and the copper or copper alloy in the abovementioneddetermination through SIMS analysis. The “wiring internal portion otherthan an interface region with the barrier metal” is the portion of thecopper or copper alloy film that is 20 nm or farther from the barriermetal/copper (alloy) interface in the copper or copper alloy film thatis surrounded by the barrier metal film.

Adhesion of the copper wiring and the barrier metal film can beenhanced, and the reliability of the wiring can be increased through thestructure of the present invention described above, i.e., by adopting astructure in which an oxide of the barrier metal film is not present inthe portion where the surface of the barrier metal film is in contactwith the grain boundaries of the copper or copper alloy film, and bymaking the average oxygen concentration in the copper or copper alloywiring 4×10¹⁸ atoms/cm³ or less. The reliability of the wiring isimproved by making the oxygen concentration in the copper wiring film atleast 4×10¹⁸ atoms/cm³ or less, and eliminating peaks in the oxygenconcentration in the interface between the barrier metal and the copper.

When a copper film formed on a wiring trench or a via is heated to ahigh temperature, oxygen (indicated by black circles in the drawing)diffuses into the copper film from the natural oxide film formed on thecopper film surface, as shown in FIG. 1, and the barrier metal oxidizesto the interface of the barrier metal and the copper. Therefore, in thepresent invention, the copper film is heated to a high temperature of200° C. or higher after an oxygen absorption film, in which the absolutevalue of the standard energy of formation of the oxidation reaction inthe range from room temperature to 400° C. is larger than that of thebarrier metal film, is formed on the copper film surface as shown inFIG. 2. The natural oxide film on the surface of the copper film isthereby bonded with the metal that constitutes the aforementioned oxygenabsorption film, whereby oxygen diffusion into the copper film isprevented, and oxygen as an impurity included in the copper film isabsorbed. A semiconductor device having the aforementioned wiringstructure can thereby be obtained. Crystal grains of copper arepreferably grown, and impurities and voids in the film are preferablyreduced in advance by heating at a low temperature of 200° C. or lessprior to forming the oxygen absorption film on the copper film surface.

The aforementioned copper film is a copper plating film having a copperalloy film as a seed in which a solid solution is formed with an addedelement for which the absolute value of the standard energy of formationof the oxidation reaction in the range from room temperature to 400° C.is larger than that of the barrier metal film. The oxygen in thevicinity of the interface of the barrier metal and the copper canthereby be trapped on the surface of the copper alloy film used as theseed, and the reliability of the interface can therefore be furtherincreased. However, the absolute value of the standard energy offormation of the oxidation reaction of the metal element that forms asolid solution with the copper in this case must be equal to or lessthan that of the oxygen absorption film formed on the copper film. Thereason for this is that absorption of oxygen must be performed primarilyby the oxygen absorption film formed on the surface of the copperplating film. Since the oxygen absorption film portion is removed in asubsequent CMP step, a copper film of even higher purity can be obtainedby this method. When the same element as the metal of the oxygenabsorption film forms a solid solution in the seed, the concentration ofthe added element in the seed is low, being from several parts permillion to several atomic percent, most of the oxygen can therefore beabsorbed by the oxygen absorption film formed on the upper surface, anda high-purity copper film can also be obtained.

The thickness of the oxygen absorption film formed on the copper filmsurface is adequate as long as it is a thickness necessary for absorbingoxygen on the copper film surface through a mechanism in which the metalatoms that constitute the oxygen absorption film chemically react withand fix the surface oxygen. The film thickness is set to 100 Å or lessto obtain an extremely thin film so that most of the film participatesin bonding with oxygen. Specifically, diffusion of the metal elementthat constitutes the oxygen absorption film into the copper film ispreferably prevented as much as possible. This is so that the resistanceof the copper wiring is not increased by diffusion of the metal elementthat constitutes the oxygen absorption film, and that voids do not occurin the copper film, particularly in the minute vias, due to theKirkendall effect. It has been confirmed that the oxygen concentrationin the copper alloy film increases due to bonding of oxygen with theadded element in the copper alloy film when the concentration of theadded element in the copper film is high. The concentration of the addedelement is therefore preferably 10¹⁹ atoms/cm³ or less.

Effects of the Invention

Adhesion of the copper wiring and the barrier metal film can beenhanced, and electromigration resistance and stress migrationresistance can be enhanced through the use of the semiconductor deviceand the method for manufacturing the semiconductor device according tothe present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view showing the behavior of oxygen in the copperfilm in the conventional technique;

FIG. 2 is a schematic view showing the behavior of oxygen in the copperfilm according to the present invention;

FIG. 3 is a diagram showing an overview of the cross-sectional structureof a portion of the wiring structure in Embodiment 1 of the presentinvention;

FIG. 4 is a sectional view showing the manufacturing method according toEmbodiment 1 of the present invention;

FIG. 5 is a diagram showing an overview of the cross-sectional structureof a portion of the wiring structure in Embodiment 2 of the presentinvention;

FIG. 6 is a sectional view showing the manufacturing method according toEmbodiment 2 of the present invention;

FIG. 7 is a diagram showing the concentration distribution of oxygen,copper, and tantalum in wiring in which the conventional technique andthe present invention are applied;

FIG. 8 is a diagram showing the metal concentration distributionincluding aluminum in wiring in which the conventional technique and thepresent invention are applied;

FIG. 9 is a diagram showing the concentration distribution of oxygen andthe added element in wiring in which the conventional technique and thepresent invention are applied;

FIG. 10 is a diagram showing the concentration distribution of oxygen,copper, and tantalum in wiring in which the conventional technique andthe present invention are applied;

FIG. 11 is a diagram showing the metal concentration distributionincluding aluminum in wiring in which the conventional technique and thepresent invention are applied;

FIG. 12 is a schematic diagram showing the concentration distribution ofoxygen and the added element in wiring in which the conventionaltechnique and the present invention are applied;

FIG. 13 is a diagram showing the rate of defect occurrence of a viachain pattern in isothermal storage testing (150° C.) of wiring in whichthe conventional technique and the present invention are applied;

FIG. 14 is a sectional view showing the semiconductor device in whichthe present invention is applied;

FIG. 15 is a sectional view showing the semiconductor device in whichthe present invention is applied;

FIG. 16 is a sectional view showing the semiconductor device in whichthe present invention is applied;

FIG. 17 is a sectional view showing the semiconductor device in whichthe present invention is applied;

FIG. 18 is a sectional view showing the semiconductor device in whichthe present invention is applied;

FIG. 19 is a sectional view showing the semiconductor device in whichthe present invention is applied; and

FIG. 20 is a sectional view showing the semiconductor device in whichthe present invention is applied.

KEY

-   -   1 semiconductor substrate    -   2 interlayer insulation film    -   3 a, 3 b etch-stop film    -   4 a, 4 b, 4 c barrier metal film    -   5 a, 5 b copper or copper alloy wiring    -   5 c copper or copper alloy via    -   6 a, 6 b wiring protective film    -   7 via interlayer insulation film    -   9 via-layer hard mask    -   10 a, 10 b wiring interlayer insulation film    -   11 a, 11 b wiring trench    -   11 c via hole    -   12 copper or copper alloy seed film    -   13 copper plating film    -   14 oxygen absorption film    -   15 a, 15 b, 15 c low-oxygen-concentration copper film    -   16 a, 16 b, 16 c side wall protection film    -   17 a, 17 b wiring-layer hard mask

BEST MODE FOR CARRYING OUT THE INVENTION

Before the invention of the present application is described in detail,the terminology used in the present application will be described. Inthe present embodiments, the term “alloy” refers to a substance in whicha metal element other than the primary component is added to the primarycomponent. For example, in the case of “copper alloy,” the primarycomponent is copper, and a metal element other than copper is added tocreate an alloy. In the case of “copper-aluminum alloy,” the primarycomponent is copper, and aluminum is added to the copper to create analloy. Furthermore, such an alloy has another metal elementintentionally added to the primary component, and the term does notexclude the inclusion of unavoidable impurities that are included as aresult of the process. Accordingly, unavoidable impurities may also beincluded in the copper.

The term “barrier metal film” refers to a conductive film having barrierproperties that covers the side and bottom surfaces of the wiring inorder to prevent the metal elements that constitute the wiring fromdiffusing into the interlayer and/or underlayer insulation film. Forexample, when the wiring is composed of metal elements primarilycomposed of copper, high-melting metals such as tantalum (Ta), tantalumnitride (TaN), titanium nitride (TiN), and tungsten carbonitride (WCN);nitrides and the like thereof, or layered films thereof are used.

The term “semiconductor substrate” refers to the substrate on which thesemiconductor device is composed, and particularly includes not onlysubstrates created on a monocrystalline silicon substrate, but also SOI(Silicon on Insulator) substrates, TFT (Thin Film Transistor) substratesfor manufacturing liquid crystals, and other substrates.

The term “interlayer insulation film” refers to a film for insulatingand separating the wiring materials, and may be a film or the like thatincludes voids within the film to reduce capacitance between the wiringunits. Typical examples thereof may include SiO₂ and HSQ (hydrogensilsesquioxane) film (e.g., Type 12™), MSQ (methyl silsesquioxane) film(e.g., JSR-LKD™, ALCAP™, NCS™, IPS™, and HOSP™), organic polymer film(SiLK™, Flare™), SiOCH, SiOC (e.g., Black Diamond™, CORAL™, AuroraULK™,Orion™, and the like); or insulation thin films in which an organiccompound is included in the abovementioned substances; or molecular porefilm in which a cyclic organic silica starting material is used.

The “sputtering method” may be a commonly used sputtering method, butlong-slow sputtering, collimation sputtering, ionized sputtering, andother highly directional sputtering methods may also be used forenhancing the fill characteristics, enhancing film quality, andobtaining uniform film thickness in the wafer plane. When an alloy issputtered, the formed metal film can be made into an alloy film byincluding an amount of the metal other than the primary component equalto or less than the solid solution limit in the metal target in advance.

The “CMP (Chemical Mechanical Polishing) method” is a method forplanarizing irregularities that occur on the wafer surface during themultilayer wiring formation process by bringing the wafer surface intocontact with a rotating polishing pad and polishing while running apolishing fluid over the wafer surface. In wiring formation by thedamascene method, the CMP method is used particularly to remove excessmetal portions and obtain a flat wiring surface after metal is filledinto the wiring trenches or the via holes.

The term “hard mask” refers to an insulation film that is used as a maskduring wiring pattern formation. However, in the present invention, thehard mask refers to an insulation film that is layered on the interlayerinsulation film to provide protection when direct CMP is difficult toperform due to a reduction in strength caused by a reduction in theconductivity of the interlayer insulation film.

(Embodiment 1)

The wiring structure according to Embodiment 1 of the present inventionwill be described using FIG. 3. Embodiment 1 of the present invention isan embodiment in which the present invention is applied to dualdamascene wiring.

As shown in FIG. 3, in the wiring structure according to Embodiment 1 ofthe present invention, a wiring structure is formed in which aninterlayer insulation film 2 and an etch-stop film 3 a are layered on asemiconductor substrate 1 on which a semiconductor element (not shown)is formed, copper or copper alloy wiring 5 a surrounded by a barriermetal film 4 a is formed by a damascene method on the upper part of theetch-stop film 3 a, and the upper surface of the wiring is covered by awiring protective film 6 a. A via interlayer insulation film 7 and anetch-stop film 3 b are layered on the upper layer, and a via and wiringare formed by a dual damascene method. A wiring structure is formed inwhich the via and wiring are composed of copper or copper alloy wiring 5b surrounded by a barrier metal film 4 b, and the surface of the wiringis covered by a wiring protective film 6 b. An oxide of the barriermetal films 4 a, 4 b is not present in the copper or copper alloy wiring5 a, 5 b and the surface contacting portions of the barrier metal films4 a, 4 b. Furthermore, the concentration of oxygen included in thecopper or copper alloy wiring 5 a, 5 b is 4×10¹⁸ atoms/cm³ or less inthe wiring-internal portion that does not include the region of theinterface with the barrier metal.

When copper alloy wiring is formed by a copper plating film in which acopper alloy seed film is formed as a seed in which an added elementforms a solid solution, in addition to the abovementionedcharacteristics, a peak in the oxygen concentration is present at theinterface of the copper alloy seed film and the plating film.Furthermore, with the interface as the boundary, the concentration ofthe added element is high in the copper alloy seed film region of thecopper alloy film, and the concentration of the added element is low inthe copper plating film region.

When the abovementioned wiring structure is used, the adhesion betweenthe copper or copper alloy wiring 5 a, 5 b and the barrier metal films 4a, 4 b can be enhanced, and electromigration resistance and stressmigration resistance can be enhanced. Specifically, since an oxide ofthe barrier metal films 4 a, 4 b is not present in the copper or copperalloy wiring 5 a, 5 b and the surface contacting portions of the barriermetal films 4 a, 4 b, adhesion between the copper alloy wiring 5 a, 5 band the barrier metal films 4 a, 4 b can be enhanced, the activationenergy of diffusion of the metal in the copper or copper alloy wiring inthe interface, which causes stress migration and electromigration, canbe enhanced, and a significant enhancement of wiring reliability isobtained. Since the interface of the copper with another materialbecomes a pathway for void diffusion in the copper, in which the stressthat causes stress migration is a driving force, enhanced adhesion islinked to enhanced resistance to stress migration. Ionization of copperatoms is suppressed by reducing the oxygen concentration in the copperor copper alloy wiring 5 a, 5 b. Mass transfer due to ion field drift orthe like is thereby suppressed, and electromigration resistance isenhanced. When a copper alloy film is obtained by copper plating using acopper alloy film as a seed in which a solid solution is formed with anadded element for which the absolute value of the standard energy offormation of the oxidation reaction in a range from room temperature to400° C. is larger than that of the barrier metal film, since oxygen istrapped on the surface of the copper alloy seed, further effects areobtained whereby oxidation is suppressed in the barrier metal interfacewith the copper. A peak is therefore present in the oxygen concentrationin the interface of the copper alloy seed film and the plating film.Furthermore, with the interface as the boundary, the concentration ofthe added element is high in the copper alloy seed film region of thecopper alloy film, and the concentration of the added element is low inthe copper plating film region. However, the metal added element in thefilm when a copper alloy film is used contributes significantly to thewiring resistance, the metal added element diffused into the platingfilm also bonds with oxygen atoms in the film, and reduction of theoxygen concentration in the plating film is suppressed even when heattreatment is applied (see Example 2). For these reasons, theconcentration of the metal added element is preferably not increasedfurther than necessary.

The present structure can also easily be confirmed from the manufacturedproduct. The structure can be confirmed by measuring the impurityconcentration in the metal wiring when at least a portion of thestructure has multilayer wiring in semiconductor products having memorycircuits such as DRAM (Dynamic Random Access Memory), SRAM (StaticRandom Access Memory), flash memory, FRAM (Ferro Electric Random AccessMemory), MRAM (Magnetic Random Access Memory), resistance random accessmemory, and the like; microprocessors and other semiconductor productshaving logical circuits; mixed semiconductor products that employ theabovementioned types of circuits simultaneously; or SIP (Silicon InPackage) and the like in which a plurality of the abovementionedsemiconductor devices is layered. Specifically, a determination can bemade by measuring the oxygen concentration by selecting a prescribedlocation and performing SIMS (Second Ion Mass Spectroscopy). When anoxide of the barrier metal is not present, a peak or inflection point isnot present in the oxygen concentration profile in the interface of thebarrier metal and the copper or copper alloy, and the profile decreasesor increases monotonically. However, when an oxide of the barrier metalis present, a peak or inflection point is present in the oxygenconcentration profile in the interface of the barrier metal and thecopper or copper alloy, and the profile no longer increasesmonotonically or decreases monotonically. In a depth-direction analysisby SIMS analysis, since measurement is performed during sputtering, theportion detected as the interface does not have a steep concentrationgradient, as in the actual structure, and the interface region and thepresence of barrier metal oxidation must therefore be determined by thechange in the profile, as described above. Alternatively, the presenceof oxidation of the barrier metal film in the portion where the barriermetal film is in contact with the grain boundaries in the copper orcopper alloy wiring can be observed using the contrast of a TEM image inwhich the semiconductor product is cut in the cross-sectional direction.The reason for this is that when oxygen diffuses into the film from thesurface of the copper or copper alloy, the oxygen diffusion coefficientis larger in the grain boundaries than within the grains. Therefore,since oxidation of the barrier metal progresses faster in the portionsof contact between the copper grain boundaries and the barrier metal,the oxidation can easily be observed in a TEM observation image or thelike.

The method for manufacturing a semiconductor device according toEmbodiment 1 will next be described with reference to the wiringsectional view shown in FIG. 4.

First, as shown in FIG. 4A, the interlayer insulation film 2 composed ofSiO₂, the etch-stop film 3 a composed of SiCN, and a wiring interlayerinsulation film 10 a composed of SiO₂ are layered on the semiconductorsubstrate 1 in which a semiconductor element (not shown) is formed, anda wiring trench 11 a is formed in the wiring interlayer insulation film10 a by a damascene method.

Examples of films that may be used as the etch-stop film 3 a are an SiO₂film, an SiN film, an SiC film, an SiCN film, an SiOC film, an SiOCHfilm, or at least one of a film in which an organic compound is includedin the aforementioned films, a film having an organic compound as theprimary component, and a film in which SiO is included in a film havingan organic compound as the primary component. These films are filmsprovided to enhance the workability of the via hole and thedual-damascene shaped wiring trench, and may be modified according tothe intended working material. The use of SiO₂ or DVS-BCB(divinylsiloxane-benzocyclobutene) created by plasma polymerization isparticularly preferred. Alternatively, the etch-stop film 3 a may beomitted when not useful for etching.

Typical examples of the wiring interlayer insulation film 10 a mayinclude SiO₂, SiC, SiCN, HSQ (hydrogen silsesquioxane) film (e.g., Type12™), MSQ (methyl silsesquioxane) film (e.g., JSR-LKD™, ALCAP™, NCS™,IPS™, and HOSP™), organic polymer film (SiLK™, Flare™), SiOCH, SiOC(e.g., Black Diamond™, CORAL™, AuroraULK™, Orion™, and the like); orinsulation thin films in which an organic compound is included in theabovementioned substances; molecular pore film in which a cyclic organicsilica starting material is used; film in which a plurality of any ofthe abovementioned films is layered; film in which the composition ordensity of any of the abovementioned films is varied in the filmthickness direction; or film in which the via interlayer insulation filmof the abovementioned films is irradiated by UV and increased instrength.

An example of the layering structure is a structure in which a two-layerstructure composed of SiO₂/AuroraULK™ (=upper layer/lower layer) isformed, and the SiO₂ is used as a protective film for AuroraULK™ duringCuCMP, or a structure in which Black Diamond™/AuroraULK™ (=upperlayer/lower layer) is used to reduce capacitance between wiring units.

An example of the layering structure is a structure in which athree-layer structure composed of SiO₂/AuroraULK™/SiO₂/(=upperlayer/middle layer/lower layer) is formed, wherein the upper-layer SiO₂is used as a protective film for the AuroraULK™ during CuCMP, and thelower-layer SiO₂ is used as an adhesive layer.

The barrier metal film 4 a is then formed on a wiring trench 11 a asshown in FIG. 4B. The barrier metal film 4 a may be formed using asputtering method, a CVD method, an ALCVD method, or the like. Forexample, high-melting metals such as tantalum (Ta), tantalum nitride(TaN), titanium nitride (TiN), and tungsten carbonitride (WCN); nitridesand the like thereof, or layered films thereof are used. A Ta/TaN(=upper layer/lower layer) layered film is particularly preferred foruse.

Next, a copper or copper alloy seed film 12 is formed on the barriermetal film 4 a as shown in FIG. 4C, and a copper plating film 13 is thenfilled into the wiring trench 11 a by an electroplating method using thecopper or copper alloy seed film 12 as the electrode. An oxygenabsorption film 14 is then formed on the copper plating film 13 as shownin FIG. 4D. Heat treatment at a temperature in the range of 200 to 400°C. is then applied to the structure shown in FIG. 4D (the barrier metalfilm 4 a, the films 12, 13 primarily composed of copper, and the oxygenabsorption film 14), whereby the oxygen absorption film 14 reacts withthe oxygen within and on the surface of the copper plating film 13, anda low-oxygen-concentration copper film 15 a is formed on the barriermetal film 4 a as shown in FIG. 4E.

The copper or copper alloy seed film 12 may be formed by a CVD method ora sputtering method in which a copper or copper alloy target is used.The metal element included in the copper alloy target may be at leastone metal selected from aluminum, tin, titanium, tungsten, silver,zirconium, indium, and magnesium. In particular, copper aluminum alloyseed layers may be formed by an ionized sputtering method in which acopper aluminum alloy target is used that includes 0.1 to 4.0 at % ofaluminum in a copper target, and copper may be filled in by anelectroplating method using the copper aluminum alloy seed layers aselectrodes to fabricate the copper or copper alloy seed film 12. Inother words, a copper plating film 13 having a copper alloy film 12 as aseed in which a solid solution is formed with an added element for whichthe absolute value of the standard energy of formation of the oxidationreaction in the range from room temperature to 400° C. is larger thanthat of the barrier metal film 4 a is preferably used as the film 15 aprimarily composed of copper that is the copper or copper alloy film. Inthe copper plating film 15 a having the copper alloy film 12 as a seedin which the added element forms a solid solution, the absolute value ofthe standard energy of formation of the oxidation reaction of the addedelement is preferably larger than that of the barrier metal film 4 a andless than or equal to that of the metal that constitutes the oxygenabsorption film 14 formed in the aforementioned step. When an alloy seedlayer and an electroplating method are combined, the concentration ofmetal elements other than copper in the alloy wiring is less than orequal to the concentration thereof in the alloy target.

There is also a method for filling in the wiring trench by sputtering orCVD rather than the method for performing electroplating on the copperor copper alloy seed film.

The material used for the oxygen absorption film 14 is a material inwhich a standard energy of formation of the oxidation reaction in therange from room temperature to 400° C. is negative, and in which theabsolute value of the standard energy of formation is larger than thatof the barrier metal film 4 a formed in the step shown in FIG. 4C.

When an oxygen absorption film in which the standard energy of formationof the oxidation reaction is smaller than that of the barrier metal filmis formed on the copper or copper alloy film surface, oxygen in thenatural oxide film formed on the copper or copper alloy film surfacereacts during the subsequent heating step with the metal thatconstitutes the oxygen absorption film formed on the surface, andsurface oxidation of the barrier metal film due to diffusion of oxygeninto the film therefore does not occur. During the heating step, sinceoxygen components included as impurities in the copper or copper alloyfilm also react with the metal that constitutes the oxygen absorptionfilm, the oxygen concentration in the copper or copper alloy film can besignificantly reduced. A state in which oxides of the barrier metalfilms 4 a, 4 b are not present is thereby achieved at the grainboundaries included in the copper or copper alloy wiring 5 a as well asin the portions where the surfaces of the barrier metal films 4 a, 4 bare in contact. The oxygen absorption film that has reacted with theoxygen components is removed in a subsequent CMP step.

When Ta or a structure in which Ta and a nitride film thereof arelayered is used as the barrier metal, aluminum, titanium, magnesium,calcium, zirconium, beryllium, hafnium, a silicon film, or the like maybe used as the oxygen absorption film. When Ti or a structure in whichTi and a nitride film thereof are layered is used as the barrier metal,aluminum, magnesium, calcium, zirconium, beryllium, a hafnium film, orthe like may be used as the oxygen absorption film. The same barriermetal oxidation prevention effects can be obtained by an oxygenabsorption film composed of a metal in which the standard energy offormation of the oxidation reaction is negative, and in which theabsolute value of the standard energy of formation is larger than thatof the barrier metal film, regardless of whether the constituent metalthereof is in a solid solution with respect to the copper or copperalloy film.

Prescribed quantities of the oxygen absorption film 14 and thelow-oxygen-concentration copper film 15 a are then removed by CMP(Chemical Mechanical Polishing), the copper or copper alloy wiring 5 ais formed, and the upper surface thereof is covered by the wiringprotective film 6 a, as shown in FIG. 4F. The via interlayer insulationfilm 7, the etch-stop film 3 b, and a wiring interlayer insulation film10 b composed of SiO₂ are then formed in sequence on the upper surfaceof the wiring protective film 6 a, as shown in FIG. 4G.

Examples of films that may be used as the wiring protective film 6 a forcovering the upper surface of the copper or copper alloy wiring 5 a arean SiN film, an SiC film, an SiCN film, an SiOC film, an SiOCH film, orat least one of a film in which an organic compound is included in theaforementioned films, a film having an organic compound as the primarycomponent, and a film in which SiO is included in a film having anorganic compound as the primary component. For example, a DVS-BCB(divinylsiloxane-benzocyclobutene) film created by a plasmapolymerization method, or a DVS-BCB compound or the like may be used. ABCB compound is a compound formed by mixing BCB with a plurality of gasstarting materials to form a film. The specific inductive capacitybetween the wiring units can be reduced through the use of these BCBfilms.

Typical examples of the via interlayer insulation film 7 may includeSiO₂, SiC, SiCN, HSQ (hydrogen silsesquioxane) film (e.g., Type 12™),MSQ (methyl silsesquioxane) film (e.g., JSR-LKD™, ALCAP™, NCS™, IPS™,and HOSP™), organic polymer film (SiLK™, Flare™), SiOCH, SiOC (e.g.,Black Diamond™, CORAL™, AuroraULK™, Orion™, and the like); or insulationthin films in which an organic compound is included in theabovementioned substances; molecular pore film in which a cyclic organicsilica starting material is used; film in which a plurality of any ofthe above-mentioned films is layered; film in which the composition ordensity of any of the abovementioned films is varied in the filmthickness direction; or film in which the via interlayer insulation filmof the abovementioned films is irradiated by UV and increased instrength.

Examples of films that may be used as the etch-stop film 3 b are an SiO₂film, an SiN film, an SiC film, an SiCN film, an SiOC film, an SiOCHfilm, or at least one of a film in which an organic compound is includedin the aforementioned films, a film having an organic compound as theprimary component, and a film in which SiO is included in a film havingan organic compound as the primary component. These films are filmsprovided to enhance the workability of the via hole and thedual-damascene shaped wiring trench, and may be modified according tothe intended working material. The use of SiO₂ or DVS-BCB(divinylsiloxane-benzocyclobutene) created by plasma polymerization isparticularly preferred. Alternatively, the etch-stop film 3 b may beomitted when not useful for etching.

Typical examples of the wiring interlayer insulation film 10 b mayinclude SiO₂, SiC, SiCN, HSQ (hydrogen silsesquioxane) film (e.g., Type12™), MSQ (methyl silsesquioxane) film (e.g., JSR-LKD™, ALCAP™, NCS™,IPS™, and HOSP™), organic polymer film (SiLK™, Flare™), SiOCH, SiOC(e.g., Black Diamond™, CORAL™, AuroraULK™, Orion™, and the like); orinsulation thin films in which an organic compound is included in theabovementioned substances; molecular pore film in which a cyclic organicsilica starting material is used; film in which a plurality of any ofthe abovementioned films is layered; film in which the composition ordensity of any of the abovementioned films is varied in the filmthickness direction; or film in which the via interlayer insulation filmof the abovementioned films is irradiated by UV and increased instrength.

An example of the layering structure is a structure in which a two-layerstructure composed of SiO₂/AuroraULK™ (=upper layer/lower layer) isformed, and the SiO₂ is used as a protective film for AuroraULK™ duringCuCMP, or a structure in which Black Diamond™/AuroraULK™ (=upperlayer/lower layer) is used to reduce capacitance between wiring units.

An example of the layering structure is a structure in which athree-layer structure composed of SiO₂/AuroraULK™/SiO₂/(=upperlayer/middle layer/lower layer) is formed, wherein the upper-layer SiO₂is used as a protective film for the AuroraULK™ during CuCMP, and thelower-layer SiO₂ is used as an adhesive layer.

A via hole 11 c and a wiring trench 11 b are then formed by a dualdamascene method as shown in FIG. 4H. The barrier metal film 4 b is thenformed on the via hole 11 c and the wiring trench 11 b, and alow-oxygen-concentration copper film 15 b is formed on the barrier metalfilm 4 b, as shown in FIG. 4I. The oxygen absorption film 14 used toform the low-oxygen-concentration copper film 15 b is then layered onthe low-oxygen-concentration copper film 15 b. The same method andmaterial as those of the underlayer wiring (15 a, 14) are used in theformation described above.

Prescribed quantities of the oxygen absorption film 14 and thelow-oxygen-concentration copper film 15 b are then removed by CMP, andafter the copper or copper alloy wiring 5 b is formed, the upper surfaceis covered by the wiring protective film 6 b.

Examples of films that may be used as the wiring protective film 6 b forcovering the upper surface of the copper or copper alloy wiring 5 b arean SiN film, an SiC film, an SiCN film, an SiOC film, an SiOCH film, orat least one of a film in which an organic compound is included in theaforementioned films, a film having an organic compound as the primarycomponent, and a film in which SiO is included in a film having anorganic compound as the primary component. For example, a DVS-BCB(divinylsiloxane-benzocyclobutene) film created by a plasmapolymerization method, or a DVS-BCB compound or the like may be used. ABCB compound is a compound formed by mixing BCB with a plurality of gasstarting materials to form a film. The specific inductive capacitybetween the wiring units can be reduced through the use of these BCBfilms.

Use of the wiring structure described above makes it possible to preventoxidation of the barrier metal in the portions in which the barriermetal films 4 a, 4 b are in contact with the grain boundaries in thecopper or copper alloy wiring 5 a, 5 b. Since adhesion between thecopper or copper alloy wiring 5 a, 5 b and the barrier metal films 4 a,4 b is thereby enhanced, electromigration resistance and stressmigration resistance can be enhanced.

The present invention is not limited to a damascene wiring trenchprocessing method.

(Embodiment 2)

The wiring structure according to Embodiment 2 of the present inventionwill be described with reference to FIG. 5. Embodiment 2 of the presentinvention is an embodiment in which the present invention is applied tosingle damascene wiring.

As shown in FIG. 5, in the wiring structure according to Embodiment 2 ofthe present invention, a wiring structure is formed in which theinterlayer insulation film 2 and the etch-stop film 3 a are layered onthe semiconductor substrate 1 in which a semiconductor element (notshown) is formed, copper or copper alloy wiring 5 a surrounded by thebarrier metal film 4 a is formed by a single damascene method in theupper part, and the upper surface of the wiring is covered by the wiringprotective film 6 a. On the upper layer thereof, the via interlayerinsulation film 7 and a via-layer hard mask 9 are layered, and a via isformed in the inside by the single damascene method. The via is formedby a copper or copper alloy via 5 c that is surrounded by a barriermetal film 4 c. On the upper layer, wiring formed by the singledamascene method is provided, and the wiring is formed by copper orcopper alloy wiring 5 b surrounded by the barrier metal film 4 b. Thesurface of the copper or copper alloy wiring 5 b is covered by thewiring protective film 6 b. An oxide of the barrier metal films 4 a, 4b, 4 c is not present in the grain boundaries included in the copper orcopper alloy wiring 5 a, 5 b and the copper or copper alloy via 5 c, andin the portion in contact with the surface of the barrier metal films 4a, 4 b, 4 c. Furthermore, the oxygen concentration included in thecopper or copper alloy wiring 5 a, 5 b and the copper or copper alloyvia 5 c is 4×10¹⁸ atoms/cm³ or less in the wiring internal part thatdoes not include the interface region with the barrier metal.

When the copper alloy wiring is formed by a copper plating film in whicha copper alloy seed film is formed as a seed in which an added elementforms a solid solution, in addition to the abovementionedcharacteristics, a peak in the oxygen concentration is present at theinterface of the copper alloy seed film and the plating film.Furthermore, with the interface as the boundary, the concentration ofthe added element is high in the copper alloy seed film region of thecopper alloy film, and the concentration of the added element is low inthe copper plating film region.

When the abovementioned wiring structure is used, the adhesion betweenthe barrier metal films 4 a, 4 b, 4 c and the copper or copper alloywiring 5 a, 5 b and copper or copper alloy via 5 c can be enhanced, andelectromigration resistance and stress migration resistance can beenhanced. Specifically, since an oxide of the barrier metal films 4 a, 4b is not present in the copper or copper alloy wiring 5 a, 5 b andcopper or copper alloy via 5 c and the surface contacting portions ofthe barrier metal films 4 a, 4 b, 4 c, adhesion between the barriermetal films 4 a, 4 b, 4 c and the copper or copper alloy wiring 5 a, 5 band copper or copper alloy via 5 c can be enhanced, the activationenergy of diffusion of the metal in the copper or copper alloy wiring inthe interface, which causes stress migration and electromigration, canbe enhanced, and a significant enhancement of wiring reliability isobtained. Since the interface of the copper with another materialbecomes a pathway for void diffusion in the copper, in which the stressthat causes stress migration is a driving force, enhanced adhesion islinked to enhanced resistance to stress migration. Ionization of copperatoms is suppressed by reducing the oxygen concentration in the copperor copper alloy wiring 5 a, 5 b and the copper or copper alloy via 5 c.Mass transfer due to ion field drift or the like is thereby suppressed,and electromigration resistance is enhanced. When a copper alloy film isobtained by copper plating using a copper alloy film as a seed in whicha solid solution is formed with an added element for which the absolutevalue of the standard energy of formation of the oxidation reaction in arange from room temperature to 400° C. is larger than that of thebarrier metal film, since oxygen is trapped on the surface of the copperalloy seed, further effects are obtained whereby oxidation is suppressedin the barrier metal interface with the copper. A peak is thereforepresent in the oxygen concentration in the interface of the copper alloyseed film and the plating film. Furthermore, with the interface as theboundary, the concentration of the added element is high in the copperalloy seed film region of the copper alloy film, and the concentrationof the added element is low in the copper plating film region. However,the metal added element in the film when a copper alloy film is usedcontributes significantly to the wiring resistance, the metal addedelement diffused into the plating film also bonds with oxygen atoms inthe film, and reduction of the oxygen concentration in the plating filmis suppressed even when heat treatment is applied (see Example 2). Forthese reasons, the concentration of the metal added element ispreferably not increased further than necessary.

The present structure can also easily be confirmed from the manufacturedproduct. The structure can be confirmed by measuring the impurityconcentration in the metal wiring when at least a portion of thestructure has multilayer wiring in DRAM (Dynamic Random Access Memory),SRAM (Static Random Access Memory), flash memory, FRAM (Ferro ElectricRandom Access Memory), MRAM (Magnetic Random Access Memory), orsemiconductor products having memory circuits such as resistance randomaccess memory and the like; microprocessors and other semiconductorproducts having logical circuits; mixed semiconductor products thatemploy the abovementioned types of circuits simultaneously; or SIP(Silicon In Package) and the like in which a plurality of theabovementioned semiconductor devices is layered. Specifically, adetermination can be made by measuring the oxygen concentration byselecting a prescribed location and performing SIMS (Second Ion MassSpectroscopy). When an oxide of the barrier metal is not present, a peakor inflection point is not present in the oxygen concentration profilein the interface of the barrier metal and the copper or copper alloy,and the profile decreases or increases monotonically. However, when anoxide of the barrier metal is present, a peak or inflection point ispresent in the oxygen concentration profile in the interface of thebarrier metal and the copper or copper alloy, and the profile no longerincreases monotonically or decreases monotonically. In a depth-directionanalysis by SIMS analysis, since measurement is performed duringsputtering, the portion detected as the interface does not have a steepconcentration gradient, as in the actual structure, and the interfaceregion and the presence of barrier metal oxidation must therefore bedetermined by the change in the profile, as described above.Alternatively, the presence of oxidation of the barrier metal film inthe portion where the barrier metal film is in contact with the grainboundaries in the copper or copper alloy wiring can be observed usingthe contrast of a TEM image in which the semiconductor product is cut inthe cross-sectional direction. The reason for this is that when oxygendiffuses into the film from the surface of the copper or copper alloy,the oxygen diffusion coefficient is larger in the grain boundaries thanwithin the grains. Therefore, since oxidation of the barrier metalprogresses faster in the portions of contact between the copper grainboundaries and the barrier metal, the oxidation can easily be observedin a TEM observation image or the like.

The method for manufacturing a semiconductor device according toEmbodiment 2 will next be described with reference to the wiringsectional view shown in FIG. 6.

First, as shown in FIG. 6A, the interlayer insulation film 2 composed ofSiO₂, the etch-stop film 3 a composed of SiCN, and the wiring interlayerinsulation film 10 a composed of SiO₂ are layered on the semiconductorsubstrate 1 in which a semiconductor element (not shown) is formed, anda wiring trench 11 a is formed in the wiring interlayer insulation film10 a by a damascene method.

Examples of films that may be used as the etch-stop film 3 a are an SiO₂film, an SiN film, an SiC film, an SiCN film, an SiOC film, an SiOCHfilm, or at least one of a film in which an organic compound is includedin the aforementioned films, a film having an organic compound as theprimary component, and a film in which SiO is included in a film havingan organic compound as the primary component. These films are filmsprovided to enhance the workability of the via hole and thedual-damascene shaped wiring trench, and may be modified according tothe intended working material. The use of SiO₂ or DVS-BCB(divinylsiloxane-benzocyclobutene) created by plasma polymerization isparticularly preferred. Alternatively, the etch-stop film 3 a may beomitted when not useful for etching.

Typical examples of the wiring interlayer insulation film 10 a mayinclude SiO₂, SiC, SiCN, HSQ (hydrogen silsesquioxane) film (e.g., Type12™), MSQ (methyl silsesquioxane) film (e.g., JSR-LKD™, ALCAP™, NCS™,IPS™, and HOSP™), organic polymer film (SiLK™, Flare™), SiOCH, SiOC(e.g., Black Diamond™, CORAL™, AuroraULK™, Orion™, and the like); orinsulation thin films in which an organic compound is included in theabovementioned substances; molecular pore film in which a cyclic organicsilica starting material is used; film in which a plurality of any ofthe abovementioned films is layered; film in which the composition ordensity of any of the abovementioned films is varied in the filmthickness direction; or film in which the via interlayer insulation filmof the abovementioned films is irradiated by UV and increased instrength.

An example of the layering structure is a structure in which a two-layerstructure composed of SiO₂/AuroraULK™ (=upper layer/lower layer) isformed, and the SiO₂ is used as a protective film for AuroraULK™ duringCuCMP, or a structure in which Black Diamond™/AuroraULK™ (=upperlayer/lower layer) is used to reduce capacitance between wiring units.

An example of the layering structure is a structure in which athree-layer structure composed of SiO₂/AuroraULK™/SiO₂ (=upperlayer/middle layer/lower layer) is formed, wherein the upper-layer SiO₂is used as a protective film for the AuroraULK™ during CuCMP, and thelower-layer SiO₂ is used as an adhesive layer.

The barrier metal film 4 a is then formed on a wiring trench 11 a asshown in FIG. 6B. The barrier metal film 4 a may be formed using asputtering method, a CVD method, an ALCVD method, or the like. Forexample, high-melting metals such as tantalum (Ta), tantalum nitride(TaN), titanium nitride (TiN), and tungsten carbonitride (WCN); nitridesand the like thereof, or layered films thereof are used. A Ta/TaN(=upper layer/lower layer) layered film is particularly preferred foruse.

Next, a copper or copper alloy seed film 12 is formed on the barriermetal film 4 a as shown in FIG. 6C, and a copper plating film 13 is thenfilled into the wiring trench 11 a by an electroplating method using thecopper or copper alloy seed film 12 as the electrode. An oxygenabsorption film 14 is then formed on the copper plating film 13 as shownin FIG. 6D. Heat treatment at a temperature in the range of 200 to 400°C. is then applied to the structure shown in FIG. 6D (the barrier metalfilm 4 a, the films 12, 13 primarily composed of copper, and the oxygenabsorption film 14), whereby the oxygen absorption film 14 reacts withthe oxygen within and on the surface of the copper plating film 13, anda low-oxygen-concentration copper film 15 a is formed on the barriermetal film 4 a as shown in FIG. 6E.

The copper or copper alloy seed film 12 may be formed by a CVD method ora sputtering method in which a copper or copper alloy target is used.The metal element included in the copper alloy target may be at leastone metal selected from aluminum, tin, titanium, tungsten, silver,zirconium, indium, and magnesium. In particular, copper aluminum alloyseed layers may be formed by an ionized sputtering method in which acopper aluminum alloy target is used that includes 0.1 to 4.0 at % ofaluminum in a copper target, and copper may be filled in by anelectroplating method using the copper aluminum alloy seed layers aselectrodes to fabricate the copper or copper alloy seed film 12. Inother words, a copper plating film 13 having a copper alloy film 12 as aseed in which a solid solution is formed with an added element for whichthe absolute value of the standard energy of formation of the oxidationreaction in the range from room temperature to 400° C. is larger thanthat of the barrier metal film 4 a is preferably used as the film 15 aprimarily composed of copper. In the copper plating film 15 a having thecopper alloy film 12 as a seed in which the added element forms a solidsolution, the absolute value of the standard energy of formation of theoxidation reaction of the added element is preferably larger than thatof the barrier metal film 4 a and less than or equal to that of themetal that constitutes the oxygen absorption film 14 formed in theaforementioned step. When an alloy seed layer and an electroplatingmethod are combined, the concentration of metal elements other thancopper in the alloy wiring is less than or equal to the concentrationthereof in the alloy target.

There is also a method for filling in the wiring trench by sputtering orCVD rather than the method for performing electroplating on the copperor copper alloy seed film.

The material used for the oxygen absorption film 14 is a material inwhich a standard energy of formation of the oxidation reaction in therange from room temperature to 400° C. is negative, and in which theabsolute value of the standard energy of formation is larger than thatof the barrier metal film 4 a formed in the step shown in FIG. 6C.

When an oxygen absorption film in which the standard energy of formationof the oxidation reaction is smaller than that of the barrier metal filmis formed on the copper or copper alloy film surface, oxygen in thenatural oxide film formed on the copper or copper alloy film surfacereacts during the subsequent heating step with the metal thatconstitutes the oxygen absorption film formed on the surface, andsurface oxidation of the barrier metal film due to diffusion of oxygeninto the film therefore does not occur. During the heating step, sinceoxygen components included as impurities in the copper or copper alloyfilm also react with the metal that constitutes the oxygen absorptionfilm, the oxygen concentration in the copper or copper alloy film can besignificantly reduced. A state in which oxides of the barrier metalfilms 4 a, 4 b are not present is thereby achieved at the grainboundaries included in the copper or copper alloy wiring 5 a as well asin the portions where the surfaces of the barrier metal films 4 a, 4 bare in contact. The oxygen absorption film that has reacted with theoxygen components is removed in a subsequent CMP step.

When Ta or a structure in which Ta and a nitride film thereof arelayered is used as the barrier metal, aluminum, titanium, magnesium,calcium, zirconium, beryllium, hafnium, a silicon film, or the like maybe used as the oxygen absorption film. When Ti or a structure in whichTi and a nitride film thereof are layered is used as the barrier metal,aluminum, magnesium, calcium, zirconium, beryllium, a hafnium film, orthe like may be used as the oxygen absorption film. The same barriermetal oxidation prevention effects can be obtained by an oxygenabsorption film composed of a metal in which the standard energy offormation of the oxidation reaction is negative, and in which theabsolute value of the standard energy of formation is larger than thatof the barrier metal film, regardless of whether the constituent metalthereof is in a solid solution with respect to the copper or copperalloy film.

Prescribed quantities of the oxygen absorption film 14 and thelow-oxygen-concentration copper film 15 a are then removed by CMP(Chemical Mechanical Polishing), the copper or copper alloy wiring 5 ais formed, and the wiring protective film 6 a and the via interlayerinsulation film 7 are formed in sequence on the upper surface, as shownin FIG. 6F.

Examples of films that may be used as the wiring protective film 6 a forcovering the upper surface of the copper or copper alloy wiring 5 a arean SiN film, an SiC film, an SiCN film, an SiOC film, an SiOCH film, orat least one of a film in which an organic compound is included in theaforementioned films, a film having an organic compound as the primarycomponent, and a film in which SiO is included in a film having anorganic compound as the primary component. For example, a DVS-BCB(divinylsiloxane-benzocyclobutene) film created by a plasmapolymerization method, or a DVS-BCB compound or the like may be used. ABCB compound is a compound formed by mixing BCB with a plurality of gasstarting materials to form a film. The specific inductive capacitybetween the wiring units can be reduced through the use of these BCBfilms.

Typical examples of the via interlayer insulation film 7 may includeSiO₂, SiC, SiCN, HSQ (hydrogen silsesquioxane) film (e.g., Type 12™),MSQ (methyl silsesquioxane) film (e.g., JSR-LKD™, ALCAP™, NCS™, IPS™,and HOSP™), organic polymer film (SiLK™, Flare™), SiOCH, SiOC (e.g.,Black Diamond™, CORAL™, AuroraULK™, Orion™, and the like); or insulationthin films in which an organic compound is included in theabovementioned substances; molecular pore film in which a cyclic organicsilica starting material is used; film in which a plurality of any ofthe above-mentioned films is layered; film in which the composition ordensity of any of the abovementioned films is varied in the filmthickness direction; or film in which the via interlayer insulation filmof the abovementioned films is irradiated by UV and increased instrength.

The via hole 11 c is then formed, and the barrier metal film 4 c and alow-oxygen-concentration copper film 15 c are formed therein as shown inFIG. 6G. In the low-oxygen-concentration copper film 15 c, heattreatment is applied after the oxygen absorption film is formed on theupper surface, in the same manner as the underlayer wiring. Prescribedquantities of the oxygen absorption film 14 and thelow-oxygen-concentration copper film 15 c are then removed by CMP(Chemical Mechanical Polishing), and the copper or copper alloy via 5 cis formed, as shown in FIG. 6H.

The etch-stop film 3 b and the wiring interlayer insulation film 10 bare then formed in sequence as shown in FIG. 6I, and the barrier metalfilm 4 b and the low-oxygen-concentration copper film 15 b are formed.In the low-oxygen-concentration copper film 15 b, heat treatment isapplied after the oxygen absorption film is formed on the upper surface,in the same manner as the underlayer wiring.

Typical examples of the wiring interlayer insulation film 10 b mayinclude SiO₂, SiC, SiCN, HSQ (hydrogen silsesquioxane) film (e.g., Type12™), MSQ (methyl silsesquioxane) film (e.g., JSR-LKD™, ALCAP™, NCS™,IPS™, and HOSP™), organic polymer film (SiLK™, Flare™), SiOCH, SiOC(e.g., Black Diamond™, CORAL™, AuroraULK™, Orion™, and the like); orinsulation thin films in which an organic compound is included in theabovementioned substances; molecular pore film in which a cyclic organicsilica starting material is used; film in which a plurality of any ofthe abovementioned films is layered; film in which the composition ordensity of any of the abovementioned films is varied in the filmthickness direction; or film in which the via interlayer insulation filmof the abovementioned films is irradiated by UV and increased instrength.

An example of the layering structure is a structure in which a two-layerstructure composed of SiO₂/AuroraULK™ (=upper layer/lower layer) isformed, and the SiO₂ is used as a protective film for AuroraULK™ duringCuCMP, or a structure in which Black Diamond™/AuroraULK™ (=upperlayer/lower layer) is used to reduce capacitance between wiring units.

An example of the layering structure is a structure in which athree-layer structure composed of SiO₂/AuroraULK™/SiO₂/(=upperlayer/middle layer/lower layer) is formed, wherein the upper-layer SiO₂is used as a protective film for the AuroraULK™ during CuCMP, and thelower-layer SiO₂ is used as an adhesive layer.

Prescribed quantities of the oxygen absorption film and thelow-oxygen-concentration copper film 15 b are then removed by CMP, andthe copper or copper alloy wiring 5 b is formed, after which the uppersurface is covered by the wiring protective film 6 b composed of SiCN.

Use of the wiring structure described above makes it possible to preventoxidation of the barrier metal in the portions in which the barriermetal films 4 a, 4 b, 4 c are in contact with the grain boundaries inthe copper or copper alloy wiring 5 a, 5 b and the copper or copperalloy via 5 c. Since adhesion between the barrier metal films 4 a, 4 b,4 c and the copper or copper alloy wiring 5 a, 5 b and copper or copperalloy via 5 c is thereby enhanced, electromigration resistance andstress migration resistance can be enhanced. The damascene wiring trenchprocessing method does not limit the present invention.

EXAMPLE 1

An example of the present invention will be described using FIG. 7. FIG.7 shows the oxygen concentration profile in the films when the Ta/TaNlayered film is formed as the barrier metal film, and the copper seedfilm, the copper plating film, and the oxygen absorption film composedof an Al thin film having a thickness of 3 nm are formed in sequence onthe upper surface, and the assembly is heated at 350° C. in themanufacturing steps shown in FIGS. 4E and 6E. The oxygen concentrationprofile in the conventional structure in which heat is applied withoutforming the oxygen absorption film is also shown simultaneously as acomparative example. The lesser depth is towards the Cu plating film. Acase is shown in which the barrier metal film is formed on the siliconoxide film formed on the silicon substrate, and the oxygen concentrationprofile is calculated by SIMS analysis from the side of the back surfaceof the substrate. Therefore, oxygen is detected inside the barrier metalfilm, but the oxygen is from the base silicon oxide film, and oxygen isconfirmed to be absent inside the barrier metal film.

In the conventionally structured wiring, the oxygen concentrationprofile has an inflection point in the interface of the Ta film and theCu, and the oxygen concentration increases in the interface portion.Specifically, oxidation of the Ta film is confirmed. In the structurethat uses the oxygen absorption film according to the present invention,an inflection point is not present in the oxygen concentration profilein the interface of Cu and the Ta film, and the change is monotonic.Specifically, it was confirmed that the Ta film was not oxidized. At theinflection point of the oxygen concentration profile of the interface ofCu and the Ta film in the conventional structure, the oxygenconcentration increased to a value of 10²⁰ atoms/cm³ or higher. FIG. 8shows the results of analyzing the aluminum concentration profile in thecopper film in the structure by SIMS analysis from the back surface inthe same manner as in FIG. 7. The lesser depth is towards the Cu platingfilm. There was no diffusion into the copper film in the vicinity of thebarrier metal film (in the range of 300 nm from the barrier film) evenfrom heating at 350° C. in the oxygen absorption film composed ofaluminum having a thickness of 3 nm that was formed on the upper surfaceof the copper film, and aluminum was not included in the copper portionremaining as wiring that was not removed by CMP performed in thesubsequent step. Therefore, in the present example, there was noobserved increase in wiring resistance in comparison to the conventionalstructure. FIG. 9 is a schematic view of the profiles of oxygen and theadded element when the effects of oxygen on the back surface of thesubstrate are excluded from the SIMS profiles shown in FIGS. 7 and 8.When the aluminum thickness is high, since more Al is present than theamount necessary for bonding with oxygen, Al diffuses into the copperfilm, and the wiring resistance increases. Since voids also occurparticularly in minute vias in the copper film due to the Kirkendalleffect, it is important that the thickness of Al be 10 nm or less (100 Å(Angstrom) or less), as in the present example.

Use of the wiring structure according to the manufacturing methoddescribed above enabled electromigration resistance and stress migrationresistance to be enhanced without increasing the wiring resistance.

EXAMPLE 2

An example of the present invention will be described using FIG. 10.FIG. 10 shows the oxygen concentration profile in the films when theTa/TaN layered film is formed as the barrier metal film, and the copperaluminum alloy seed film, the copper plating film, and the oxygenabsorption film composed of an Al thin film are formed in sequence onthe upper surface, and the assembly is heated at 350° C. in themanufacturing steps shown in FIGS. 4E and 6E. The oxygen concentrationprofile in the conventional structure in which heat is applied withoutforming the oxygen absorption film is also shown simultaneously as acomparative example. The lesser depth is towards the Cu plating film. Acase is shown in which the barrier metal film is formed on the siliconoxide film formed on the silicon substrate, and the oxygen concentrationprofile is calculated by SIMS analysis from the side of the back surfaceof the substrate. Therefore, oxygen is detected inside the barrier metalfilm, but the oxygen is from the base silicon oxide film, and oxygen isconfirmed to be absent inside the barrier metal film. FIG. 11 shows theresults of measuring the aluminum concentration profile by SIMS analysisfrom the surface side in the copper film in the same structure as inFIG. 10. The lesser depth is towards the Cu plating film. FIG. 12 is aschematic view of the profiles of oxygen and the added element when theeffects of oxygen on the back surface of the substrate are excluded fromthe SIMS profiles shown in FIGS. 10 and 11.

In the conventionally structured wiring, an inflection point is presentin the oxygen concentration profile in the interface of Cu and the Tafilm, and the oxygen concentration increases in the interface portion,as is apparent from FIG. 10. Specifically, oxidation of the Ta film isconfirmed. In the structure that uses the oxygen absorption filmaccording to the present invention, an inflection point is not presentin the oxygen concentration profile in the interface of Cu and the Tafilm, and the change is monotonic. Specifically, it was confirmed thatthe Ta film was not oxidized. Also, since a copper aluminum alloy filmwas used as the seed in the present example, oxygen was trapped by theseed film surface in the conventional structure and the structure of thepresent invention, but the oxygen concentration in the copper alloy filmin the conventional structure was higher than the oxygen concentrationin the copper film in the conventional structure when the copper filmshown in FIG. 7 was used. The reason for this is that the oxygen in thecopper film was difficult to reduce even when heat treatment was appliedin the copper alloy film, due to bonding of oxygen atoms with the metaladded element. A region in which the oxygen concentration in the copperplating film was 4×10¹⁸ atoms/cm³ or higher was present in theconventionally structured wiring, but in the structure that uses theoxygen absorption film according to the present invention, the oxygenconcentration was clearly reduced to 4×10¹⁸ atoms/cm³ or less, and itwas apparent that the oxygen in the copper aluminum alloy film can alsobe absorbed by the oxygen absorption film composed of aluminum. In thestructure of the present invention, since the copper aluminum alloy filmwas used as the seed as is apparent from FIG. 11, the aluminumconcentration was high in certain regions of the seed film near thebarrier, and the aluminum concentration was low in the copper platingfilm. As is determined from FIGS. 10 and 11, and FIG. 12 showing theconcentration profiles of oxygen or the added element as derived fromFIGS. 10 and 11, the change in the added element concentration in thecopper has an oxygen peak at the interface of the copper plating filmregion and the copper alloy seed film region. In the present example,the aluminum concentration in the copper aluminum seed film region is onthe order of 10¹⁹ atoms/cm³, and the aluminum concentration in thecopper plating film region is on the order of 10¹⁸ atoms/cm³. Thisconcentration is set so as not to increase the resistance of the copperwiring more than necessary, and to a value whereby the oxygenconcentration in the copper alloy film does not increase more thannecessary due to bonding of oxygen and the metal added element in thecopper alloy film. FIG. 13 shows the storage time dependency of thedefect occurrence rate of a 100 nm (diameter) via chain pattern(upper-layer wiring and lower-layer wiring width: 3.0 μm) in stressmigration testing (storage at 150° C.) performed using wiring in theconventional structure and the structure of the present invention. Chipsin which the resistance increased by 5% or more from the initialresistance were determined to be defective. As the results show, thewiring structure of the present example having such characteristics asthose described above had a lower rate of defect occurrence due tostress migration than the conventional structure.

A necessary condition for the combination of the type of atoms of theoxygen absorption film and the added element diffused into the copperfilm from the alloy seed film was that the standard energy of formationof the oxidation reaction in the range from room temperature to 400° C.of the atoms constituting the oxygen absorption film be negative, andthat the absolute value of the standard energy of formation be largerthan that of the atoms constituting the barrier metal. However, theabsolute value of the standard energy of formation is preferably largerthan or the same as that of the added element. For example, when theadded element is Al, as in Example 2 described above, Al, Mg, Ca, Zr,Be, Hf, or the like is preferred as the oxygen absorption film. When theadded element is Sn or Mn, the oxygen absorption film is preferably Al,Ti, Mg, Ca, Zr, Be, Hf, or the like.

EXAMPLE 3

An example of a semiconductor device in which the present invention isimplemented will be described using the wiring sectional view shown inFIG. 14. A semiconductor device having the structure shown in FIG. 14was obtained by processing without the use of the etch-stop film 3 b inthe step for processing the via hole 11 c and the wiring trench 11 b bythe dual damascene method described using FIG. 4H in the semiconductordevice described in Embodiment 1.

Through the use of the wiring structure described above, theelectromigration resistance and the stress migration resistance wereenhanced, the effective inductance of the wiring was reduced, andparasitic capacitance between wiring units was reduced.

EXAMPLE 4

In a semiconductor device having the cross section shown in FIG. 4Jdescribed in Embodiment 1, DVS-BCB (divinylsiloxane-benzocyclobutene)films fabricated by plasma polymerization were used as wiring protectivefilms 6 a, 6 b, whereby electromigration resistance and stress migrationresistance were enhanced, the effective inductance of the wiring wasreduced, and parasitic capacitance between wiring units was reduced.

A DVS-BCB film includes large quantities of organic components as awiring protective film, and has poor adhesion to copper or copper alloyrelative to a film primarily composed of Si. Therefore, siliciding thesurface of the copper or copper alloy is sometimes used to enhanceadhesion when a DVS-BCB film is formed on the wiring. The inventorslearned through investigation that when silicon that has diffused intothe inside from the surface of the copper or copper alloy wiringdiffuses to the surface of the barrier metal film at this time, an oxideof the silicon is formed in the barrier metal surface in theconventional technique, which significantly compromises the reliabilityof the wiring. The reliability of the wiring was therefore enhanced byapplying the present invention to a DVS-BCB film in which a silicidingtreatment was used.

EXAMPLE 5

An example of a semiconductor device in which the present invention isimplemented will be described using the wiring sectional view shown inFIG. 15. A semiconductor device having the structure shown in FIG. 15was obtained by forming DVS-BCB (divinylsiloxane-benzocyclobutene) filmsfabricated by plasma polymerization as side-wall protective films 16 a,16 c, 16 b for protecting the side walls in the step for processing thewiring trench 11 a, the via hole 11 c, and the wiring trench 11 b by thedual damascene method described using FIGS. 4A and 4H in thesemiconductor device described in Embodiment 1.

Through the use of the wiring structure described above, theelectromigration resistance and the stress migration resistance wereenhanced, and leakage between wiring units was reduced by the effects ofprotecting the side walls of the interlayer insulation film. Significanteffects were obtained particularly when a porous film such as AuroraULK™was used as at least a portion of the wiring interlayer films 10 a, 10 band the via interlayer film 7.

EXAMPLE 6

An example of a semiconductor device in which the present invention isimplemented will be described using the wiring sectional view shown inFIG. 16. A semiconductor device having the structure shown in FIG. 16was obtained by using the porous film AuroraULK™ and the SiO₂ layeredstructure of the wiring-layer hard mask (the wiring-layer hard mask isindicated by 17 a and 17 b in FIG. 16) as the wiring interlayerinsulation films 10 a, 10 b, and using Black Diamond™ or AuroraULK™ inthe via interlayer insulation film 7 of the wiring structure shown inFIG. 4J described in Embodiment 1 or Example 4.

The electromigration resistance and stress migration resistance wereenhanced through the use of the wiring structure described above, andthrough the use of AuroraULK™ and Black Diamond™ having lower specificinductance than SiO₂, the effective inductance of the wiring wasreduced, and parasitic capacitance between wiring units was reduced.

EXAMPLE 7

A Black Diamond™ film was used as the wiring-layer hard masks 17 a and17 b, and AuroraULK™ was used as the via interlayer insulation film 7shown in FIG. 16 described in Example 6, whereby the electromigrationresistance and stress migration resistance were enhanced, the effectiveinductance of the wiring was reduced, and parasitic capacitance betweenwiring units was reduced.

EXAMPLE 8

An example of a semiconductor device in which the present invention isimplemented will be described using the wiring sectional view shown inFIG. 17. A semiconductor device having the structure shown in FIG. 17was obtained by using the porous film AuroraULK™ and the SiO₂ layeredstructure of the wiring-layer hard mask (the wiring-layer hard mask isindicated by 17 a and 17 b in FIG. 17) as the wiring interlayerinsulation films 4 a, 4 b, and using AuroraULK™ also in the viainterlayer insulation film 7 of the wiring structure shown in FIG. 4Jdescribed in Example 3.

Through the use of the wiring structure described above, theelectromigration resistance and the stress migration resistance wereenhanced, the effective inductance of the wiring was reduced, andparasitic capacitance between wiring units was reduced.

EXAMPLE 9

An example of a semiconductor device in which the present invention isimplemented will be described using the wiring sectional view shown inFIG. 18. A semiconductor device having the structure shown in FIG. 18was obtained by forming DVS-BCB (divinylsiloxane-benzocyclobutene) filmsfabricated by plasma polymerization as side-wall protective films 16 a,16 c, 16 b for the side walls of the wiring and the via in the wiringstructure of FIG. 16 described in Example 6.

Through the use of the wiring structure described above, theelectromigration resistance and the resistance to stress-induced voidingwere enhanced, and leakage between wiring units was reduced by theeffects of protecting the side walls of the interlayer insulation film,and the interface of the wiring interlayer insulation film and the hardmask.

EXAMPLE 10

An example of a semiconductor device in which the present invention isimplemented will be described using the wiring sectional view shown inFIG. 19. A semiconductor device having the structure shown in FIG. 19was obtained by using the porous film AuroraULK™ and the SiO₂ layeredstructure of the wiring-layer hard mask (the wiring-layer hard mask isindicated by 17 a and 17 b in FIG. 19) as the wiring interlayerinsulation films 10 a, 10 b, and using Black Diamond™ in the viainterlayer insulation film 7 of the wiring structure shown in FIG. 6Jdescribed in Embodiment 2.

The electromigration resistance and stress migration resistance wereenhanced through the use of the wiring structure described above, andthrough the use of AuroraULK™ and Black Diamond™ having lower specificinductance than SiO₂, the effective inductance of the wiring wasreduced, and parasitic capacitance between wiring units was reduced.

EXAMPLE 11

An example of a semiconductor device in which the present invention isimplemented will be described using the wiring sectional view shown inFIG. 20. A semiconductor device having the structure shown in FIG. 20was obtained by forming DVS-BCB (divinylsiloxane-benzocyclobutene) filmsfabricated by plasma polymerization as side-wall protective films 16 a,16 b for the side walls of the wiring in the wiring structure of FIG. 19described in Example 10.

Through the use of the wiring structure described above, theelectromigration resistance and stress migration resistance wereenhanced, and leakage between wiring units was reduced by the effects ofprotecting the side walls of the interlayer insulation film, and theinterface of the wiring interlayer insulation film and the hard mask.

Industrial Applicability

The present invention is universally applicable, and the scope ofapplicability of the present invention is unlimited insofar as theapplication relates to the wiring structure of multilayer wiringcomposed of a wiring structure in which a copper alloy primarilycomposed of copper is used as the wiring material, and to a method formanufacturing the wiring structure.

The present invention was described in relation to several preferredembodiments and examples, but the embodiments and examples were givenmerely as examples for describing the present invention, and do notlimit the present invention.

For example, the present invention was described in detail in relationto a technique for manufacturing a semiconductor device having CMOScircuits in the background field of the invention developed by theinventors, but the present invention is not thus limited. For example,the present invention can also be applied to semiconductor productshaving memory circuits such as DRAM (Dynamic Random Access Memory), SRAM(Static Random Access Memory), flash memory, FRAM (Ferro Electric RandomAccess Memory), MRAM (Magnetic Random Access Memory), resistance randomaccess memory, and the like; microprocessors and other semiconductorproducts having logical circuits; and mixed semiconductor products thatemploy the abovementioned types of circuits simultaneously. The presentinvention can also be applied to semiconductor devices, electroniccircuit devices, optical circuit devices, quantum circuit devices,micro-machines, and the like that have embedded alloy wiring structuresin at least a portion thereof.

The present invention may include various modifications in a technicalrange based on the claims of the present application, and the technicalrange of the present invention is in no way limited by the embodimentsand examples of the present invention.

1. A semiconductor device having a copper or copper alloy filmpositioned in at least one layer, and a barrier metal film for coveringa periphery of wiring that is formed in a prescribed region in aninsulation film formed on top of a semiconductor substrate, wherein anoxide of the barrier metal film is not present in a region in which saidcopper or copper alloy film is in contact with the barrier metal film,and wherein a concentration of oxygen included in said copper or copperalloy film is 4×10¹⁸ atoms/cm³ or less in a wiring internal portionother than an interface region with said barrier metal film.
 2. Asemiconductor device having a copper or copper alloy film positioned inat least one layer, and a barrier metal film for covering a periphery ofwiring that is formed in a prescribed region in an insulation filmformed on top of a semiconductor substrate, wherein an oxide of thebarrier metal film is not present in a region in which said copper orcopper alloy film is in contact with the barrier metal film, said copperor copper alloy film is a copper plating film formed using a copperalloy seed film as a seed in which a solid solution is formed with anadded element, and an oxygen concentration peak is present in a platingfilm interface with the copper alloy seed film.
 3. A semiconductordevice having a copper or copper alloy film positioned in at least onelayer, and a barrier metal film for covering a periphery of wiring thatis formed in a prescribed region in an insulation film formed on top ofa semiconductor substrate, wherein an oxide of the barrier metal film isnot present in a region in which said copper or copper alloy film is incontact with the barrier metal film, said copper or copper alloy film isa copper plating film formed using a copper alloy seed film as a seed inwhich a solid solution is formed with an added element, a concentrationof said added element is high in a copper alloy seed film region of saidcopper or copper alloy film, and a concentration of said added elementis low in a copper plating film region.